Apparatus for analyzing rotary motion



NOV. 4, 1969 Q, BLAfEK ET AL APPARATUS FOR ANALYZING ROTARY MOTION FiledApril 11, 1968 United States Patent Office 3,475,973 Patented Nov. 4,1969 APPARATUS FOR ANALYZING ROTARY MOTION Otta Blazek, Plzen, MiloriHerynk, Chrast, and Josef Rybai, Lhota, Czechoslovakia, assignors toSkoda,

narodni podnik, Plzen, Czechoslovakia Filed Apr. 11, 1968, Ser. No.720,737 Claims priority, application Czechoslovakia, Apr. 11, 1967,2,622/67 Int. Cl. F16h 19/04 U.S. C]. 74-29 6 Claims ABSTRACT OF THEDISCLOSURE The rotary motion of a body about an axis is analyzed interms of rectangular Cartesian coordinates by slides guided in pathsperpendicular to each other and to the axis of rotation and each fixedlycarrying an engaging arm formed with a slot enlongated at right anglesto the path of the associated slide. An eccentric coupling pin on thebody whose motion is to be analyzed is simultaneously received in bothslots. A rack on each slide engages a pinion on the input member of aselsyn so that the output signals of the selsyns are indicative of theposition of the pin in Cartesian coordinates.

BACKGROUND OF THE INVENTION This invention relates to the analysis ofrotary motion in terms of Cartesian coordinates, and particularly toapparatus for generating signals indicative of the position of a bodymoving in an arcuate path relative to a system of Cartesian coordinates.

The problems which can be solved by such apparatus are examplified bythe milling machine for milling crankshafts disclosed in the copending,commonly assigned application of Frantisek Rozanek et al., filed on orabout Jan. 24, 1968, in which a milling cutter is moved in a circularpath by means of a supporting head arranged to move the cutter in twodirections perpendicular to each other, while the crankshaft to bemachined rotates about its axis.

SUMMARY OF THE INVENTION The apparatus of the invention may consistmainly of two guides which define respective rectilinear paths extendingin the direction of the desired Cartesian coordinates which aretransverse of the axis of rotation of the body to be analyzed andtransverse of each other. Actuator members respectively guided in thesepaths carry fixedly fastened engaging elements each of which engages thesame eccentric coupling member on the rotating body in such a mannerthat the engaging element moves with the coupling member in thedirection of the path of the associated actuator member while permittingthe coupling member to move freely relative to the engaging element inthe direction of the path of the other actuator member. The actuatormembers each operate a signal generator which produces a signal inresponse to the position of the connected actuator member in the paththereof.

The exact nature of this invention as well as other features, objectsand advantages thereof will .be readily apparent from consideration ofthe following specification relating to the annexed drawing.

BRIEF DESCRIPTION OF THE DRAWING The sole figure of the drawing showsthe analyzing apparatus of the invention in fragmentary elevationalview.

DESCRIPTION OF THE PREFERRED EMBODIMENT The body 1 whose rotary motionis to be analyzed is a crankshaft 1, not shown in detail, on which aneccentric,

cylindrical coupling pin 2 is attached by means of a radial arm 21. Twoelongated arms 3, 4 are attached at right angles to elongated slides 5,6 respectively which are guided on respective guide bars 7, 8 inrectilinear paths perpendicular to each other and perpendicular to theaxis of rotation of the shaft 1. The guide bars 7, 8 are fixed elementsof a supporting frame of the machine, not otherwise shown, in which theshaft 1 is journaled in a nonillustrated conventional manner.

The arms 3, 4 have respective longitudinal slots 31, 41 whoselongitudinal walls are spaced apart approximately by the diameter of thepin 2. The pin 2 is simultaneously received in both slots 31, 41 inabutting engagement with the faces of the longitudinal walls, the arms3, 4 being superimposed in the direction of the axis of the shaft 1.

Racks 9, 10 respectively cut into longitudinal faces of the slides 5, 6mesh with pinions 13, 14 respectively mounted on the input shafts 15, 16of two selsyns 11, 12 fixedly arranged on the stationary supportstructure for converting the rectilinear movement of the slides 5, 6into angular movement of the shafts 15, 16.

When the shaft 1 rotates clockwise from the position shown in thedrawing, the coupling pin 2 slowly moves the engaging arm 3 and theslide 6 upward, as viewed in the drawing, whereby the input shaft 16 ofthe selsyn 12 is turned clockwise. Simultaneously, the pin 2 moves at ahigher speed longitudinally in the slot 31, but this movement has noeffect on the position of the input shaft 16.

Also, the arm 4 on the slide 5 is moved toward the left, as viewed inthe drawing, by the pin 2, and the input shaft 15 of the selsyn 11 ismoved counterclockwise. The free longitudinal movement of the pin 2 inthe slot 41 does not affect the position of the selsyn 11.

The output signals of the selsyns 11, 12 are amplified in a conventionalmanner and fed to two servomotors in the aforementioned milling machinewhich shift the milling cutter along respective paths perpendicular toeach other. If the two servomechanisms are identical, the milling headis moved thereby in a circle in synchronization with the circularmovement performed by the pin 2 during rotation of the shaft 1.

It will be appreciated that the apparatus illustrated may readily bemodified to analyze the rotary motion of the shaft 1 in terms of obliqueCartesian coordinates if the two rectilinear movements of the millingmachine head are obliquely inclined relative to each other.Servomechanisms of the type specifically described above permit theoutput signals generated by the selsyns 11, 12 in response to thepositions of the actuating slides 5, 6 to be modified in a simple mannerby conventional electronic controls on the associated amplifiers, andelectronic or electrical signal generators are therefore preferred. Theslides 5, 6 may be employed in an obvious manner for actuatingmechanical, hydraulic, or pneumatic signal generators in an obviousmanner to produce signals indicative of the position of the pin 2 inCartesian coordinates.

It should be understood, therefore, that the foregoing disclosurerelates only to a preferred embodiment of the invention, and that it isintended to cover all changes and modifications of the example of theinvention chosen herein for the purpose of the disclosure which do notconstitute departures from the spirit and scope of the invention setforth in the appended claims.

What is claimed is:

1. In an apparatus for analyzing the rotary motion of a body about anaxis in terms of two Cartesian coordinates transverse of said axis andtransverse of each other, in combination:

(a) two guide means defining respective rectilinear paths extending in adirection of said coordinates respectively;

(b) two actuator members respectively mounted on said guide means andguided by the associated guide means in said paths;

(c) a coupling member spaced on said body from said axis for circularmovement of the coupling member about said axis during said rotarymotion of said body;

(d) engaging means fixedly fastened to each of said actuator members andengaging said coupling member for movement of the engaging means withsaid coupling member in the direction of the path of the associatedactuator member while permitting said coupling member to move freelyrelative to said engaging means in the direction of the path of theother actuator member; and

(e) two signal generating means operatively connected to said actuatormembers respectively for generating signals in response to the positionsof the connected actuating members in the paths thereof.

2. In an apparatus as set forth in claim 1, said paths beingperpendicular to each other and to said axis.

3. In an apparatus as set forth in claim 1, said engaging means eachhaving two abutment faces oppositely spaced in the direction of saidpath of the associated actuator member and extending in the direction ofsaid path of the other actuator member, the spacing of said faces beingsubstantially equal to the dimension of said coupling member in thelast-mentioned direction, the coupling member being received betweensaid faces.

4. In an apparatus as set forth in claim 3, each engaging meansincluding an engaging member formed with an opening elongated in thedirection of said path of the other actuator member, said facesextending in said openmg.

5. In an apparatus as set forth in claim 1, motion transmitting meansinterposed between each actuator member and the associated signalgenerating means for converting the rectilinear movement of saidactuator member into angular movement of said signal generating means,the signal generating means including an angularly movable input memberconnected to said motion transmitting means for operation thereby.

6. In an apparatus as set forth in claim 5, said motion transmittingmeans including a rack on said actuator member, and said input membercarrying a pinion meshing with said rack.

References Cited UNITED STATES PATENTS 405,636 6/1889 Wilcomb 74292,859,628 11/1958 Arko 74422 2,991,663 7/ 1961 McHugh 74422 3,220,27611/1965 Bruns 74422 FOREIGN PATENTS 925,793 3/ 1947 France.

FRED C. MATTERN, 1a., Primary Examiner W. S. RATLIFF, 1a., AssistantExaminer

